Need A Little Help with a Roller Coaster I'm Making

I just started scripting so i was bored so im making a very simple roller coaster. All i did was made a cart, and like 15 feet away or so (something like that) i made an invisible cube. I linked them and made the cube the parent prim. I then made it where the cart rotates around the parent prim so the cart goes in a big circle whenever you sit(hardly a roller coaster, i know). And i made it where u click to sit and that it stops when you stand and with text commands and all those goodies. The only problem is, if i try to sit, he sits on the parent prim, rather than in the cart. I need the invisible cube to be the parent prim so that it is the axis so that the cart goes in a full perfect circle. If i made the cart the parent prim, yes, he would start sitting in it, but the cart would just be rotating and the invisible sphere would be going in a circle around me. How do i make it where he automatically sits in the cart?

I think if you put a sit target in your cart, this should alleviate the problem. Search the scripting tips forum for Sit Target Helper. It's a wonderful thing.

The other thing I could suggest is cutting your parent prim so that it does not have available sit surface. It's invisible, it shouldn't matter how it looks, and the center won't change with the cutting.

yeah i tried making the parent prim unsittable but it always is. i even made an unsittible object, and then when i attached it as parent prim, it was all the sudden sittable. Even if i put it under ground he sits under there.